1. Investigation of Band-Offsets at Monolayer–MultilayerMoS2Junctions by Scanning Photocurrent Microscopy.
- Author
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Sarah L. Howell, Deep Jariwala, Chung-Chiang Wu, Kan-Sheng Chen, VinodK. Sangwan, Junmo Kang, TobinJ. Marks, Mark C. Hersam, and Lincoln J. Lauhon
- Subjects
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MOLYBDENUM selenides , *ENERGY bands , *MONOMOLECULAR films , *PHOTOCURRENTS , *HETEROJUNCTIONS , *ELECTRIC potential measurement , *CHARGE carriers - Abstract
Thethickness-dependent band structure of MoS2implies thatdiscontinuities in energy bands exist at the interface of monolayer(1L) and multilayer (ML) thin films. The characteristics of such heterojunctionsare analyzed here using current versus voltage measurements, scanningphotocurrent microscopy, and finite element simulations of chargecarrier transport. Rectifying I–Vcurves are consistently observed between contacts on opposite sidesof 1L/ML junctions, and a strong bias-dependent photocurrent is observedat the junction. Finite element device simulations with varying carrierconcentrations and electron affinities show that a type II band alignmentat single layer/multilayer junctions reproduces both the rectifyingelectrical characteristics and the photocurrent response under bias.However, the zero-bias junction photocurrent and its energy dependenceare not explained by conventional photovoltaic and photothermoelectricmechanisms, indicating the contributions of hot carriers. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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